Cutting tool for valve seats



June 23, 1970 P. R. RENDA l lL- 3'-;'516,329

CUTTING TOOL FOR VALVE SEATS Filed July 5, 1968 INVENTOR. LPhillip @Qenclohl ATTORN EYS United States Patent 3,516,329 CUTTING TOOL FOR VALVE SEATS Phillip R. Rendahl, R0. Box 1114, Central Valley, Calif. 96019 Filed July 3, 1968, Ser. No. 742,368 Int. Cl. B23: 1/20 US. Cl. 90-125 6 Claims ABSTRACT OF THE DISCLOSURE A tool selectively operative to resurface the valve seat of an engine, to narrow the valve seat by top-cutting and bottom-cutting therealong and to cut a groove or channel for receipt of a replaceable valve seat ring therewithin. The tool includes an axially extending body adapted to be rotated by a wrench attached thereto, and the body is equipped with a stem-like pilot receivable within the engine-provided valve guide associated with any such seat to enforce a condition of concentricity upon the tool body relative thereto. The tool body is adjustably supported by the pilot, and it is provided with a plurality of slots each having a cutting blade disposed therewithin. Each blade is selectively movable along its slot into operative positions from which it performs one or more of the aforementioned cutting operations.

This invention relates to a cutting tool and, more particularly, to an improved cutting tool selectively operative to resurface valve seats, to narrow the same by top-cutting and bottom-cutting thereof, and to cut a groove or channel for receipt of a replaceable valve seat ring therewithin.

Internal combustion engines are provided with valve structures which control the admission of a combustible mixture of fuel and air into a cylinder space for ignition therewithin and which also control efiiux of the subsequent products of combustion therefrom. Extended use of such an engine results in deterioration of the closures defined by the cooperative engagement of such valve structures and the seats therefor, and such deterioration reduces the efficiency and effectiveness of the engine but can be cured by resurfacing the valve seat and then providing or grinding a valve to matingly engage the same. Since the requirement for valve reconditioning is a common problem, many tool structures have been devised to effect the seat resurfacing process.

An object of the present invention is to provide an improved cutting tool for resurfacing and otherwise cutting surfaces associated with a valve seat, and which tool requires no attachment to the cylinder head or other engine surfaces surrounding a valve seat so that use of the tool is not limited by the characteristics of such surfaces and there is no danger of misalignment or other improper positioning of the tool as a consequence of such characteristics of those surfaces. Another object of the invention is in the provision of a tool of the type described that uses a single cutting blade during any cutting operation, thereby avoiding chatter and other malfunctioning characterizing multiple cutters which often cause rough surface finishing. Still another object is that of providing a cutting tool as described which is adjustable for all valve sizes throughout a wide range and employs a pilot receivable within the valve guide associated with any valve seat so as to enforce a condition of substantial concentricity upon the tool as respects any such seat, and which pilot enables the tool to be instantly removed and replaced during use to enable frequent inspection of the work being performed thereby.

A further object is to provide a cutting tool selectively operative to resurface a valve seat, to narrow the same when necessary by top-cutting and/or by bottom-cutting Patented June 23, 1970 the seat, and to cut a groove or channel with sufficiently close tolerance to enable a replaceable seat to be mounted therein with a straight press fit. Still further objects, among others, are to provide a tool that is compact and portable, has wide range of adjustability, can be speedily set up for operation, is exceedingly versatile in that the single tool is able to instantly cut, locate and narrow the entire size range of valve seats found in automotive use, and which tool is so simple in construction and operation that mechanics with minimum training and experience can use the tool successfully. Additional objects and advantages of the invention will become apparent as the specification develops.

An embodiment of the invention is illustrated in the accompanying drawing, in which:

FIG. 1 is a perspective view of a cutting tool embodying the invention;

FIG. 2 is a side view in elevation on reduced scale showing the cutting tool in operative association with a valve opening of an internal combustion engine;

FIG. 3 is a side view in elevation illustrating the cut ting tool being used to cut a groove for receipt of a replaceable valve seat ring in a standard-size internal combustion engine;

FIG. 4 is a broken side view in elevation, similar to that of FIG. 3, showing the tool being used to cut or resurface a valve seat;

FIG. 5 is a broken side view in elevation similar to that of FIG. 4, showing the tool being used to narrow the valve seat by undercutting the same;

1 FIG. 6 is a broken side view in elevation, similar to that of FIG. 4, showing the tool being used to narrow the valve seat by top-cutting the same;

FIG. 7 is a broken side view in elevation, similar to that of FIG. 4, showing the tool being used to cut or resurface a smaller-diameter valve seat such as present in a lawnmower engine;

FIG. 8 is a broken side view in elevation, similar to that of FIG. 7, showing use of the tool to narrow such smaller-diameter valve seat by top-cutting the same; and

FIG. 9 is a transverse sectional view taken along the line 9-9 of FIG. 3.

The cutting tool which is shown in its entirety in FIGS. 1, 2 and 3 is denoted generally with the numeral 10, and comprises an axially extending body 11 having a bore 12 (FIG. 3) extending axially therethrough. Removably mounted within the bore 12 is a cylindrical shaft defiining a pilot 13 having approximately the same diameter as that of the bore 12 so as to be slidably and rotatable receivable therewithin. The body 11 adjacent the upper end thereof is provided with a hexagonal portion defining a wrench-receiving drive nut 14, which wrench is used to rotate the tool and is engageable with the drive nut as shown in FIG. 2. Any suitable device can be used to rotate the tool 10, and for purposes of specific illusration the wrench shown in FIG. 2 is a ratchet-type socket wrench generally denoted 15.

The bore 12 through the nut 14 is enlarged adjacent its upper end portion and is threaded, as shown at 16. Engageable with the internal threads 16 is a lock nut 17 which is externally threaded to cooperate with the threads 16, and the lock nut is also internally threaded so as to receive therewithin an adjustable stop 18 in the form of a threaded bolt. The lock nut 17 is a split component (as shown in FIG. 9), and is slightly tapered so as to be wedged into tight frictional engagement with the stop bolt 18 to constrain the same in any position of adjustment thereof when the lock nut is tightened into the hexagonal upper end or drive nut 14 of the body 11. As shown in FIG. 3, the pilot 13 at its upper end is adapted to abut the adjustable stop 18, which stop therefore limits the extent to which the pilot 13 is insertable into the body 11.

The axially extending body 11 is provided along the outer cylindrical surface thereof with a plurality of slots respectively receiving cutting blades therein. In the specific tool illustrated, there are three such slots respectively denoted 19, and 21 and the blades respectively associated therewith are designtaed 22, 23 and 24. Each of the slots is generally rectangular as is the cutting blade associated therewith, and a slot 21 is axially oriented and extends along the outer surface of the body 11 in substantially parallel relation with the axis of the body. The slots 19 and 20 and blades 22 and 23 associated therewith have an angular disposition and a skewed orientation relative to the axis of the body 11. Each of the blades is adjustably and removably mounted within the associated slot therefor, and in the case of the blades 22 and 23, they are respectively constrained within their slots by engagement with the enlarged hexagonal heads of cap screws 25 and 26. The blade 24 is confined within the slot 21 therefor by a set screw 27 which is accessible through the slot 19, as shown in FIGS. 7 and 8.

The blade 22 is the longest of the three blades, and it is provided at the opposite ends thereof with cutting or knife edges 28 and 29 which can be selectively brought into a position of use, as shown in FIGS. 3 and 5 and as will be described in greater detail subsequently. The blade 23 is somewhat shorter than the blade 22, and it is also provided at the opposite ends thereof with cutting or knife edges 30 and 31 which are selectively usable, as shown in FIGS. 4 and 6. In an analogous manner, the axially disposed blade 24 is equi ed at the opposite ends thereof with cutting or knife edges 32 and 33, as shown in FIGS. 7 and 8 respectively. It will be apparent that any one of the cutting blades can be adjusted along its associated slot until a cutting edge of the blade projects outwardly a sufficient distance to engage the desired valve seat surface, and the blade is constrained in any position of adjustment by tightening the associated screw which, therefore, defines fastener structure releasably securing the cutting blade in selected positions of adjustment along its slot. In order to use one or the other cutting edges of the blade, the position thereof is simply reversed within its slot.

-As indicated hereinbefore, the tool 10 is usable in cutting surfaces associated with a valve seat of an internal combustion engine; and a typical valve opening or port is illustrated in FIG. 2. The portion of the engine shown in this figure is denoted 34, and it is provided with a valve port or opening 35 etsablishing communication between a cylinder space 36 and a flow passage 37 opening into a manifold (not shown) which may be either the intake or exhaust manifold depending upon the particular valve port being considered. Disposed below the port 35 is a valve guide 38 adapted to slidably receive therein the stern of a valve (not shown). The valve guide 38 is axially aligned with respect to the port 35 and maintains the valve therefor in a positive condition of axial alignment. As is well known, the engine 34 is equipped below the guide 38 with a cam shaft or valve lifter (not shown) controlling reciprocable displacements of any value associated therewith, and which shaft or lifter serves as a stop positively limiting downward movement of the pilot 13 by abutment therewith.

The engine 34, as shown in FIG. 2, is equipped with a replaceable valve seat ring and, accordingly, the port 35 has a seat or offset shoulder 39 formed thereabout which is adapted to receive therein a replaceable ring 40, as shown in FIGS. 4 through 8. The cutting edge 28 of the blade 22 is designed to cut the shoulder 39 and circumjacent surface thereabout, as shown in FIG. 3; and the tool is able to accommodate valve openings of different diameter simply by extending the cutting edge 28 to a greater or lesser extent as the case may require.

In use of the tool to cut the ring-receiving seat or channel providing the shoulder 39, the valve associated with the port 35 is removed as is any ring 40, and the pilot 13 is inserted into the valve guide 38. The cutting edge 28 of the blade 22 is moved outwardly to the extent required and the blade is clamped in the position of adjustment thereof by tightening the fastener 25. The depth to which the blade 22 will cut is determined by the adjustment of the stop 18 since the tool body 11 can move downwardly upon the pilot 13 only to the extent permitted by the stop 18. When all such adjustments have been made, a suitable wrench 15 is used to engage the drive nut 14 (as shown in FIG. 2), whereupon the tool 10 is rotated and the cutting end 28 of the blade 22 cuts the seat 39. If greater depth is required, the lock nut 17 is released and the stop 18 is withdrawn slightly and then locked in such new position of adjustment which permits the body 11 to move downwardly to a greater extent as metal is removed from about the opening 35.

After the seat 39 has been properly formed, the tool is removed and the ring 40 inserted into the seat 39, as shown in FIGS. 4 through 8. It has been found that a straight press fit for the ring 40 appears to obviate many problems of fit such as looseness and leakage that often result from other types of mountings, and an optimum interference of about 0.006 of an inch has been found to afford adequate crush or deformation of the ring in the size range of valves found in most automobile engines. A fit of such character does not result either in looseness of the ring or in over-stressing the same, which would cause it to lose its resiliency and take a set resulting in looseness, when the engine and ring expand during use of the engine.

After the ring 40 is in position, as shown in FIGS. 4 through 8, the tool is readjusted to bring the cutting edge 30 of the blade 23 into engagement with the upper inner edge of the ring 40 to cut the valve seat 41. Again, the tool body 11 is positioned upon the pilot 13 which is located within the valve guide 38 and the tool is rotated by the wrench 15, as previously described, to cut the seat 41. If the valve seat 14 is too wide, it may be under-cut or top-cut as respectively shown in FIGS. 5 and 6, to narrow the seat and thereby provide a better closure with the valve to be associated therewith. In the case of undercutting the seat 41, the position of the blade 22 is reversed in the slot 19 to bring the cutting edge 29 into operative association with the lower corner portion of the seat 41, as shown in FIG. 5. In the case of top-cutting the seat 41, the position of the blade 23 is reversed in the slot 20 to bring the cutting edge 31 into engagement with the upper corner of the seat 41, as shown in FIG. 6.

In the case of engines having smaller than average valve ports (as shown by the engine 34a in FIGS. 7 and 8 which has a valve port 35a defined by a ring 40a having a valve seat 41a thereabout), the blade 24 is adjusted to bring the cutting edge 32 thereof into engagement with the ring so as to cut the seat 41a. Should it be required to narrow the seat 41a, the position of the blade 24 is reversed within the slot 21 to bring the cutting edge 33 into engagement with the ring 40a to top-cut the seat 41a thereof, as shown in FIG. 8.

The tool 10 is maintained in perfect concentricity with the valve port because of the cooperative relationship of the tool, and especially the pilot 13 thereof, with the valve guide 38 of any valve port with respect to which cutting operations are to be performed. Since the tool body 11 is removably mounted upon the pilot 13, the body cutting blades thereof are instantly removable and replaceable to permit the work being performed to be inspected from time to time quickly and easily, which periodic inspection improves the general quality of the cutting operations. In this same general reference, the tool, because of the pilot 13 andassociated components, requires no attachment to the cylinder head or other engine surfaces surrounding a valve port so that operation of the tool is not limited by the characteristics of such surfaces and there is no danger of misalignment of the tool with the valve port, as is the case when such surrounding engine surfaces are so used.

Although the tool provides a plurality of cutting blades, only one blade and a cutting edge thereof is in engagement with the appropriate valve surface during any single cutting operation which makes it easy and convenient to adjust the tool, and the difficulty of adjusting and the maintaining multiple blades in adjustment is thereby obviated which eliminates chatter attributable thereto and roughness in the surface finish resulting therefrom. The tool is also adjustable through a wide range of sizes, as heretofore explained, and is quickly andeasily set up and operated. It is compact and readily portable and the single tool is able to install, cut, locate and narrow valve seats with the requirement of only a minimum of skill.

While the tool of the invention has been described with respect to the resurfacing of a valve port, it should be recognized that it is useful for performing other cutting operations on surfaces associated with the valve. For example, it can be used to enlarge the valve passage and the internal portion of a valve seat as is sometimes done to permit installation of larger valves and obtain better cylinder breathing in engines for racing cars and the like. A suitable blade may be secured within slot 19 for this purpose, and the stop 18 can be adjusted to permit the body to extend into the valve port to permit the interior cutting.

While in the foregoing specification an embodiment of the invention has been set forth in considerable detail for purposes of making a complete disclosure thereof, it will be apparent to those skilled in the art that numerous changes may be made in such details without departing from the spirit and principles of the invention.

What is claimed is:

1. A tool for cutting surfaces associated with the valve ports of an engine having for each valve port guide concentrically oriented with respect thereto for reciprocably supporting therein the stem of a valve therefor, comprising an axially extending tool body equipped with means for rotating the same, an elongated pilot defining the axis of rotation for said body and extending axially therefrom for receipt within such valve guide to enforce a condition of concentricity upon said body relative to such port, and a plurality of cutting blades adjustably carried by said body spaced distances from said axis of rotation and at least certain of said blades having a skewed orientation with respect thereto, said body being provided with a plurality of slots each slidably receiving a cutting blade therein, and fastener structure for each of said slots for releasably securing the respectively associated blades in selected positions of adustment therealong, each of said cutting blades being equipped with a cutting edge at each end thereof, one cutting edge being confifgurated to cut a valve seat, another to narrow such seat by top-cutting therealong, another to narrow such seat .by bottomcutting therealong, and still another for cutting a groove for receiving a replaceable valve seat ring therein, all of said slots being disposed at different angles or orientation relative to each other.

2. The tool of claim 1 in which structure is provided for adjustably displacing said body axially with respect to said pilot.

3. The tool of claim 2 in which said body is provided with an axially extending passage slidably receiving said pilot therein, and further comprising adjustable stop structure carried by said body and engageable with said pilot to determine the depth of penetration thereof into said passage.

4. The tool of claim 1 in which certain of said slots open at one end thereof along the perimetric surface of said body so that the associated cutting blades extend outwardly beyond the adjacent perimetric extremity of said body.

5. The tool of claim 4 in which another of said slots and the cutting blade adjustably positioned therewithin are oriented in spaced apart parallelism with such axis of rotation of said body.

6. The tool of claim 5 in which said body is provided with an axially extending passage slidably receiving said pilot therein, and further comprising adjustable stop structure carried by said body and engageable with said pilot to determine the depth of penetration thereof into said passage.

References Cited UNITED STATES PATENTS 1,964,970 7/1934 AlbertSOn. 3,391,604 7/1968 Appleby 29-125 FOREIGN PATENTS 124,923 2/1945 Australia. 1,220,437 5/1960 France.

GIL WEIDENFELD, Primary Examiner US. Cl. X.R. 29-105 

